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From: Krishna Reddy <vdumpa@nvidia.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	'Russell King - ARM Linux' <linux@arm.linux.org.uk>,
	'Arnd Bergmann' <arnd@arndb.de>, 'Joerg Roedel' <joro@8bytes.org>,
	"linaro-mm-sig@lists.linaro.org" <linaro-mm-sig@lists.linaro.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	'Kyungmin Park' <kyungmin.park@samsung.com>,
	Andrzej Pietrasiewicz <andrzej.p@samsung.com>,
	'Chunsang Jeong' <chunsang.jeong@linaro.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	'Laura Abbott' <lauraa@codeaurora.org>
Subject: RE: [Linaro-mm-sig] [PATCH 1/2] ARM: initial proof-of-concept IOMMU mapper for DMA-mapping
Date: Tue, 11 Oct 2011 11:13:31 -0700	[thread overview]
Message-ID: <401E54CE964CD94BAE1EB4A729C7087E3722519A1F@HQMAIL04.nvidia.com> (raw)
In-Reply-To: <00b101cc87ee$8976c410$9c644c30$%szyprowski@samsung.com>

Marek,

>It looks that You have simplified arm_iommu_map_sg() function too much. 
>The main advantage of the iommu is to map scattered memory pages into 
>contiguous dma address space. DMA-mapping is allowed to merge consecutive
>entries in the scatter list if hardware supports that.
>http://article.gmane.org/gmane.linux.kernel/1128416

I would update arm_iommu_map_sg() back to coalesce the sg list.

>I'm not sure if mmc drivers are aware of coalescing the SG entries together.
>If not the code must be updated to use dma_sg_len() and the dma entries
>number returned from dma_map_sg() call.

MMC drivers seem to be aware of coalescing the SG entries together as they are using dma_sg_len().

Let me test and update the patch.

--
nvpublic

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  reply	other threads:[~2011-10-11 18:13 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-02 13:56 [RFC 0/2 v2] ARM: DMA-mapping & IOMMU integration Marek Szyprowski
2011-09-02 13:56 ` [PATCH 1/2] ARM: initial proof-of-concept IOMMU mapper for DMA-mapping Marek Szyprowski
2011-09-08 16:41   ` [Linaro-mm-sig] " Laura Abbott
2011-09-21 14:50     ` Marek Szyprowski
2011-10-10 21:56       ` Krishna Reddy
2011-10-11  8:19         ` Marek Szyprowski
2011-10-11 18:13           ` Krishna Reddy [this message]
2011-10-12  1:34             ` Krishna Reddy
2011-10-12  5:49               ` Marek Szyprowski
2011-10-12  7:02                 ` Krishna Reddy
2011-10-13  0:18                   ` Krishna Reddy
2011-10-17 14:07                     ` Marek Szyprowski
2011-09-02 13:56 ` [PATCH 2/2] ARM: Samsung: update/rewrite Samsung SYSMMU (IOMMU) driver Marek Szyprowski
2011-09-05 18:21   ` Ohad Ben-Cohen
2011-09-06 10:27   ` KyongHo Cho
2011-09-06 12:35     ` [Linaro-mm-sig] " Ohad Ben-Cohen

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